Three-Terminal MLCC Electrode Thickness Control
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Solution Overview
Problem
Three-terminal multilayer ceramic capacitors face challenges in achieving large capacitance due to limitations in external electrode thickness, which affects internal electrode stacking and leads to variations in contact resistance and Equivalent Series Inductance (ESL).
Innovation Solution
A three-terminal multilayer ceramic capacitor design with specific external electrode thickness ratios and a manufacturing method involving a conductive paste with controlled specific gravity and viscosity to form a Ni underlying electrode layer, followed by plating electrode layers, ensuring optimal electrode coverage and capacitance without excessive external dimensions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the thickness of the external electrode is increased, then the external electrode can be formed more reliably and contact resistance is reduced, but the capacitive element's external dimensions must be reduced accordingly, making it difficult to obtain large capacitance
Solution Approach 1:
The patent changes the physical parameters of the conductive paste (specific gravity: 2.5-4.0 g/cm³, viscosity: 50-200 cP) to optimize the thickness of the Ni underlying electrode layer. By controlling these parameters, the paste forms a layer of 5-20 μm thickness that provides reliable electrode formation and low contact resistance while maintaining the capacitive element's external dimensions for large capacitance.
2Length of stationary object
If the thickness of the underlying electrode layer is excessively reduced, then the external dimensions can be maintained, but non-formation regions are produced and contact resistance and ESL significantly vary
Solution Approach 1:
The patent specifies precise parameter ranges for the conductive paste (specific gravity: 2.5-4.0 g/cm³, viscosity: 50-200 cP) to ensure the Ni underlying electrode layer forms with consistent thickness of 5-20 μm. This controlled parameter range prevents non-formation regions and ensures uniform contact resistance and ESL across all capacitors.
Solution Approach 2:
The patent establishes a feedback mechanism by defining specific parameter ranges for the conductive paste that directly control the underlying electrode layer thickness. By monitoring and controlling paste application parameters within these ranges, the manufacturing process ensures consistent electrode formation and electrical characteristics.
3Reliability
If the thickness of the external electrode is increased, then contact resistance is reduced, but the number of internal electrodes to be stacked must be reduced, making it difficult to obtain large capacitance
Solution Approach 1:
The patent optimizes the conductive paste parameters (specific gravity: 2.5-4.0 g/cm³, viscosity: 50-200 cP) to form an Ni underlying electrode layer of 5-20 μm thickness. This optimized thickness provides sufficient contact resistance reduction while minimizing the space occupied by external electrodes, thereby allowing maximum stacking of internal electrodes for large capacitance.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The design achieves consistent characteristics with reduced ESL variation and enables the attainment of large capacitance within specified dimensions.
Implementation Method 1
applying a conductive paste to an external surface of the green capacitive element to have a desired shape and a desired thickness for forming a Ni underlying electrode layer
Implementation Method 2
firing the green capacitive element to produce a capacitive element including a plurality of ceramic layers, and a plurality of first internal electrodes and a plurality of second internal electrodes
Data Source
AI summary
A three-terminal multilayer ceramic capacitor includes a capacitor including a ceramic layer, first and second internal electrodes, first and second end surface electrodes, and first and second side surface electrodes, and has a lengthwise dimension of about 1300 μm or more and about 1500 μm or less, a widthwise dimension of about 1000 μm or more and about 1200 μm or less, a heightwise dimension of about 570 μm or more and about 680 μm or less, and a capacitance of about 12 μF or more and about 32 μF or less. The first and second end surface electrodes, and the first and second side surface electrodes include a Ni underlying electrode layer and at least one plating electrode layer. The first and second end surface electrodes have a thickness of about 0.73% or more and about 3.00% or less relative to the lengthwise dimension.